Safety issues of psilocybin and LSD as potential rapid acting antidepressants and potential challenges.

INTRODUCTION: A limited number of preliminary open-label (n = 3) and placebo-controlled clinical trials (n = 5) have suggested psilocybin and LSD as potential rapid antidepressants. In this context, there is a growing need to verify and document their safety and tolerability as therapeutic agents, discuss the challenges associated with their administration, and develop safety protocols for their use as next-generation therapeutic agents. AREAS COVERED: We have analyzed all randomized, double-blind, and controlled trials that assessed the antidepressant effects of psilocybin and LSD in clinical populations to date, taking special attention to adverse events (AEs) related to their use. Prevalence, significance, and mechanisms of action related to AEs were systematically extracted, analyzed, and discussed. EXPERT OPINION: There were no serious AEs related to psilocybin and LSD administration. Most AEs were expected, manageable, and transient. Nevertheless, safety and tolerability concerns regarding some effects, such as dissociation, paranoia, and confusion, remain. Thus, randomized controlled trials with bigger samples are warranted to confirm their therapeutic effects and further investigate their safety and tolerability.